i just rebulit a 350 with somework done to it and its pretty much broken in almost at 500 miles...the entire time though when i drive it when im crusing at 2,000 rpm's the idle jumps up and down and i can fell the car jerking a little becuase of the idle jumping around what could be causing this?


and one mor qustion...it usally only happens when its just been started...when im driving and i stomp the gas the car hesitates and i have to let off the gass alitle and give it gas again to stop it from hesitating

 

vacuum leaks? timing?

 

Could it be the torque converter locking and unlocking?

 

well i just had my trany rebuilt and got a new tourq converter but it did it before and after...it could be the timing? i have feeling its not timed right

 

Surging at cruise speeds can be an indication of a lean condition in the carburetor. The timing is easiest to check though, so I'd do that first.

 

The most common causes are a lean condition or timing. Could also be a bad TPS or IAC.

 

how can i make it not run lean? cause i also had a feeling it was because i changed the spark plugs and thats what it looked like

 

Check for a vacuum leak somewhere. Next I would check for a clogged fuel filter, clogged injectors, low fuel pressure, or a poisoned o2 sensor.

EDIT: Could also be that you need to start tuning to get the most from your setup. You may be right on the brink of flowing to much air for the stock tune to handle.

 

Did you set the timing per sticker under hood?
Did you set the minimum Air Rate & TPS voltage?
Do you have an adjustable fuel pressure regulator?
Did you reprogram the ECM with the new injector size? If not you'll need to set the static (engine off) fuel pressure (about 37psi) to make the 24# flow at the stock rate, and increment the pressure 2psi at a time until there's now change in power which, the ECM will program out over time.
The old distributor spring, weights, stops, and fuel mixture & idle screws are now in the ECM.
Even if you're not flowing more air, you've changed things the ECM controls as if they're stock, OneBinky is right, unless it's something simple like the base timing, or base idle, vacuum leaks you'll need to do some ECM tuning, the injectors alone are 10% more than stock, and the ECM only has a ±10% auto-programming range.

 

yeah i had a chip burnt for the new motor, however, i origonally had accel 26# inj and i already had the chip, and when i started the car the injecters where crap so i got SVO inj. and i asked if i should send it back for reprograming he said to just increas the feul pressure to 60psi

i set the feul pressure with the car running and the vacume line off the afpr

 

The ratio for 22/24 is about the same as 26/24 so 37 psi will also work for the 24s if the CHIP is programmed for 26s

50-52psi will make a 24lbr flow like a 26lbr.
You may be pushing the injector past the 80% duty cycle were it can go static and trip into a 50% on 50% off duty cycle causing a lean condition which isn't good for your engine.
Icreasing the pressure a little isn't a problem, but when you force a small injector to work like a larger one your asking for trouble.

 

do u think i messed anything up bad? i drove it around so far for about 400 milles at 57-58 psi

 

Well, I'm still thinking about this because you say it's lean, but the ECM would have reduce the injector pulse width quiet a bit to make it go lean.
Back off on the fuel pressure to 37psi, reset the ECM, start it up, and let it go into closed loop, rev it in park, and make sure the exhaust manifolds, or headers do not glow red hot (very lean condition.) If every thing seems to be OK then, I would suggest a plug reading (use inexpensive plugs,) until now I've just pulled the plugs and looked at them, but I don't think that's the proper way to do it. Ask around.

 

http://www.dragstuff.com/techarticle...ead-plugs.html

 

well my headers dont glow red but as soon as i turn the motor on the get extremly hot and iv let the motor sit in park for a while and gave it a few revs but it never turned red

 

Is this as is, or have you lowered the fuel pressure?

 

that how its always been at 57-58 psi(which is what its been at the entire time iv been runing the motor) i havent lowered the feul pressure yet

 

static feul pressure is when the car is off but the key is turned on?

 

Yes, but it'll only stay on for about 2-3secs. If you don't have anyone around to cycle the key for you, you can:

1. disconnect and plug the fuel regulator vacuum line, start the engine and set the pressure.
2. Power the fuel pump by applying 12volts to the "G" terminal (lower left pin) of the ALDL connector with no key in the ignition.

 

i changed the feul pressure to 52 psi with the vac hose off and the timing is set at 6* btdc and its still doing it

 

try 30# injectors and see what happens.
i know they're not as cheap as jets,but you DO have fuel injection!
Eric

 

i dont have the money to buy a new set of injectors i jsut bought these

 

52psi is still too high.
Remember that the ECM thinks it's got 26lbers, you still need to drop the static pressure to 37psi so that the 24 will flow the correct amount of fuel, be sure to reset the ECM so it'll forget what it's learned.

You need to get it to idle properly. Set the minimum air & TPS after it's warmed up.

 

what should i set it to when the car is running then? when i set the static pressure and i turned the car on the feul pressure was still 37 psi when the car was running with the vac hose off'

 

what should i set my idle to sit its a modified motor?

 

The ECM controls the idle depending on coolant temperature.
The minimum air rate only sets the baseline idle to 450-500rpm like setting the baseline timing to 6°, once you return control to ECM it could go as high as 1200rpm when cold.
If you want to change the programmed idle settings, you'll have to burn another chip for it, which is what I did for my 388.

I posted the procedure on this thead.
Minimum Air Rate

 

i set the feul pressure to 37 psi static but when the car is running with the vac house off it is still at 37 psi...y would u wanna run that low of a psi wouldnt u want a higher psi so it would run like the 26#...eather way after i changed it to 37 psi it still did the surging and i set the idel also...if the iac was broken would it cause it to surge while driving?

 

I was making the assumption that you wanted to flow like 24s, not 26s. so increase it to 52psi, back to square one.

It wouldn't idle properly if the IAC was faulty.

 

eatherway i jsut wanted it to run right with the computer set for 26# inj with 24# i didnt no which way it was suposed to be

 

when it first starts up it idles like crap then after it warms up it runs fine but it just started doing that after i tryed adjusting the iac and i did replug it in

 

What's the compression ratio?
Are heads 60cc after milling, if not what volume are they now?

 

they where 60cc heads then they milled but they wherent really milled that much they where jsut cleaned up im not sure what the ratio is

 

Assuming the following:

• 4.00" bore
• 3.48" crank
• 60cc chamber volume
• 0.041" gasket thickness

You may be killing the spark with high compression, it's even more likely if your using regular gas, and a wide spark plug gap.
The compression ratio is about 11.5:1, too much even for premium gas. With the milling it's probably closer to 12:1, regardless you'll need high octane fuel, and 93 may not be enough.

Are you using a high performance ignition system? If not get one, trim the spark plug ground electrode so that you can see the center electrode tip from above, and gap them to .035"
if you haven't done so, try cooling the intake charge that will help alot.

 

how do you cool the intake charge? iv been using 94 octane with octane boost

and what do u mean by gaping the spark plug...just gaping it normally?

 

which ignition system would u recomend thats not very expensive mds or accel...i was looking at the msd pakaege for the hei would that fit? and also do u think geting the ignition would help solve the problem with out really having to get higher octan gas? my friend said he could dyno tune it to run on 94 octane

 

i was also thinking what about if a cylinder was missfiring? cause when i slowly accelerate i hear a little poping in the exhaust it doesnt sound like its back firing but it just sound slike it pops but as soon as i acelerate almost all the way the poping stops and the surging stops



and what about a bad egr solinoid?

 

Its becuase you have the wrong size injectors in there, like RGarcia tried to tell you 3.3 million times. It's dumping to much fuel. That popping you hear is the leftover unburnt fuel combusting in your exhaust system. If you have anything installed for a cat, you can pretty much kiss it goodbye. Also kiss any chance of passing emissions goodbye. Either put the stock injector size in the car, or learn how to program the ECM for the combo you are running. There is no way around it.

As far as ignition systems go, accell stuff is not all that great. They have huge quality control issues.

We have also had two MSD 6AL boxes on two seperate cars, and they have both failed within 1.5 years. I am running a Holley annihilator setup, and have had no issues with it. Jacobs is pretty much the best out there, but it's gonna run you a bit more money.

 

alright well i cant send my chip out any more so im jsut ganna by the stuff and learn how to burn my own chips and fix the injector sizes...is there anything else you would recomend to change to make it run better?